474 DR. J. V. HAAST ON ZIPHIUS NOV^-ZEALANDT^. [June 6, 



still the flattened appearance of the first, but in a lesser degree, after 

 which they assume all nearly the same shape, the upper portion 

 below the articulations or articulation having a prismoid form, which 

 is most pronounced in the middle of the ribs, where tbey are also the 

 most constricted, the edge being on the inner side ; they then widen 

 and flatten to their lower extremity. 



The second to the seventh rib inclusive have, like the first, two 

 articulations ; a distinct capitular process for articulation with the 

 vertebra in front, and an excavated articular surface slightly raised 

 round the edges, into which the transverse process fits. 



The eighth and ninth ribs have only one excavated surface, 

 articulating with the end of the transverse process. 



The greatest length of each rib, measured in a straight line, is : — 



ft. in. 



First 1 9± 



Second 2 6| 



Third 2 10^ 



Fourth 3 0| 



Fifth 3 2 



Sixth 3 3| 



Seventh 3 2f 



Eighth 2 Hi 



Ninth 2 5£ 



Sternum. 



In the form of the sternum Ziphius novce-zealandice shows a well- 

 marked difference from Z. australis of Buenos Aires. It consists of 

 five distinct segments, of which the first is the largest, having a greatest 

 length of 14| inches, with a greatest breadth of 124 inches. 



The second, third, and fourth segments gradually diminish in both 

 dimensions until the fifth, which is the narrowest but longer than 

 the three preceding ones. The dimensions of the fifth are 7f inches 

 in length with a breadth of G inches. 



The first, which possesses a shallow keel in its upper portion, has 

 a deep notch above it, and another in the centre of its basal portion. 

 Similar fossae exist in each of the succeeding segments, by which four 

 median fenestrse are formed, gradually dimininishing in size, having 

 their largest diameter in a vertical direction. There are six articular 

 surfaces on each side for the sternal ribs — the first near the upper 

 portion of the first segment, the second at the junction of the first 

 and second, the third at the junction of the second and third, the 

 fourth at the junction of the third and fourth, the fifth at the junction 

 of the fourth and fifth segments, and the last at the posterior ends of 

 the two narrow processes by which the fifth segment terminates. 

 The entire length of the sternum in a straight line is 3 feet 1 inch. 



A comparison with the sternum of Ziphius australis shows a great 

 difference in the form of the segments of the fenestrse ; and, as it 

 appears to me, when mature, this species would only have four seg- 

 ments instead of five, thus agreeing with Berardius arnouxi. 



